The objectives of the proposed research are an evaluation, characterization, and comparison of how the binaural auditory system processes interaural temporal disparities (ITDs) at high and low frequencies. The principal aim of the research is to investigate whether and the degree to which well-known differences in binaural processing at low and high frequencies stem from true differences in the binaural mechanisms that mediate performance or stem from inherent differences in the monaural neural information that serves as input to the binaural system. The experiments involve "transposing" or heterodyning rectified and low-passed, low-frequency information to high frequencies. We will create high-frequency stimuli whose envelopes contain information that is like that normally available from the fine-structure of stimuli presented at low frequencies. The data obtained from detection and lateralization experiments will reveal 1) the relative sensitivity to ITDs at low and high frequencies and the degree to which information available to the putative internal cross-correlation mechanism is processed similarly, as a function o center frequency and 2) the degree to which the processing of interaural disparities conveyed by transposed, high-frequency stimuli is protected from binaural "interference" that typically occurs with "conventional" high-frequency stimuli.